Like the case of an isotropic phase (hereinafter sometimes referred to as “non-liquid crystalline isotropic phase”) of a nematic liquid crystal material, the Kerr effect, which is a phenomenon in which a value of electric birefringence ΔnE (a value of birefringence induced when electric field is applied on an isotropic medium) is proportional to the square of electric field E [ΔnE=KλE2 (K: Kerr constant (Kerr coefficient), λ: wavelength)], is observed in a blue phase, which is an optically isotropic liquid crystal phase.
Recently, modes in which electric birefringence is exhibited by applying electric field to an optically isotropic liquid crystal phase such as a blue phase have been actively studied (see Japanese Laid-Open Patent Publication No. 2003-327966, No. 2005-336477, No. 2006-89622, No. 2006-299084, No. 2005-157109, and No. 2006-127707, International Publication WO 2005/90520 and WO 2005/080529 pamphlet, Japanese National-phase PCT Laid-Open Patent Publication No. 2005-537520, No. 2006-506477 and No. 2007-503487, Nature Materials, 1, 64, (2002), Adv. Mater., 17, 96, (2005), and Journal of the SID, 14, 551, (2006)). In addition, not only application of the modes to display elements, but also application thereof to wavelength-variable filters, wavefront control elements, liquid crystal lenses, aberration correction elements, aperture control elements, optical head apparatuses and the like, in which electric birefringence is utilized, have been proposed (see International Publication WO 2005/080529 pamphlet, Japanese Laid-Open Patent Publication No. 2005-157109 and No. 2006-127707).